Decorso etal
nonconsumable electrode

ABSTRACT

AN ELECTRODE HAS A BODY OR STEM PORTION CARRYING AN ELECTRODE HEAD OR ELECTRODE TIP. THE BODY OR STEM PORTION IS PROTECTED BY HEAT SHIELD MEANS EXTERNAL THERETO AND INCLUDES FLUID CHANNELING MEANS FOR CONDUCTING A COOLING FLUID FROM THE UPPER END THEREOF TOWARD THE ELECTRODE HEAD, THE FLUID CHANNELING MEANS ALSO CONDUCTING THE FLUID AFTER IT HAS PERFORMED ITS COOLING FUNCTION TOWARD THE UPPER END OF THE BODY OR STEM PORTION. AN AXIALLY EXTENDING PASSAGEWAY OPEN AT THE UPPER END THEREOF, OR WHICH MAY   BE OPENED AT THE UPPER END, EXTENDS THROUGH THE BODY OR STEM PORTION AT LEAST TO A POSITION NEAR THE ELECTRODE HEAD.

Oct. 19, 1971 s, M, DECOR-50 E'ru.v Re.27,196

NONGONSUMABLEEAELECTRODE Y 3 Sheets-Sheet 1 Original Filed May 24, 1965Oct. 19, 1.971 s. M. DEcoRso ETAL Re. 27,196

` NONCONSUMABLE ELECTRODE 3 Sheets-Sheet 2 Original Filed May 24, 1965Oct. 19, 1971 5 M, DECORSO El'AL NONCONSUMABLE ELECTRODE 5 Shoots-Sheet5 Original Filed May 24, 1965 Int. Cl. H05b 7 08 U.S. Cl. 13-18 30Claims Matter enclosed in heavy brackets appears in the original patentbut forms no part of this reissue specification; matter printed initalics indicates the additions made by reissue.

ABSTRACT OF THE DISCLOSURE An electrode has a body or stem portioncarrying an electrode head or electrode tip. The body or stem portion isprotected by heat shield means external thereto and United States PatentO includes fluid channeling means for conducting a cooling v fluid fromthe upper end thereof toward the electrode head, the fluid channelingmeans also conducting the #uid after it has performed its coolingfunction toward the up per end of the body or stem portion. An axiallyextending passageway open at the upper end thereof, or which may beopened at the upper end, extends through the body or stern portion atleast to a position near the electrode head.

This invention relates to improvements in arc electrodes, and moreparticularly to an improved non-consumable arc electrode especiallysuitable for use in a furnace.

Although it is old in the art to employ electric arcs for melting inelectric furnaces for metal processing, heretofore it has been thepractice to use electrodes composed of graphite or carbon, whichelectrodes are continuously used up during the melting process, so thatin order to maintain the arcing distance between the electrode and themelt Within desirable or useful limits, it was necessary to continuallyreadjust the position of the electrode and move it continually in thedirection of the melt as the arcing surface was eaten away or consumedby the arc therefrom. Where the electrode of our invention is employed,it is usually necessary to adjust the position of the electrode axiallyonly when there is a change in the level of the melt, or when materialis added or removed.

In a copending application of A. M. Bruning for "Nonconsumable Electrodefor Electric Arc Heating and Melting and It/Iethoa's, Ser. No. 866,274,filed Oct. 14, 1969, now Pat. No. 3,561,029 which application is acontinuation-in-part of an application for Electric Arc Furnace andNonconsumable Electrode Suitable for Use Therein, Ser. No. 407,332,filed Oct. 29, 1964, [and] now abandoned, both assigned to the assigneeof the instant invention, there is described and claimed a substantiallynonconsumable electrode in which a water cooled arcing surface isprovided, with magnetic field producing means for substantiallycontinually moving the arc around the arcing surface to prevent burnthrough, and the non-consumable electrode of the Bruning patentapplication has a useful life order of magnitude greater than the lifeof a consumable carbon or graphite electrode.

In a copending application of S. M. De Corso and C. B. Wolf forNon-Consumable Arc Electrode, filed Oct- 29, 1964, Ser. No. 407,327, nowissued Patent No. 3,398,229 and assigned to the assignee of the instantapplication, there is described and claimed a substantially cylindricalhollow electrode with a water cooled arcing surface, the electrodeincluding a plurality of concentric tubes providing passageways for theflow of fluid to and from the elecice trode face member or arcingsurface, and also a space for bringing leads to an arc-moving magneticfield coil disposed in the electrode face member, one or more of thetubes of the last-named copending application carrying electricalcurrent to the arcing surface to produce the arc.

The invention described and claimed herein represents an improvementover, and advance in the art over, the electrodes of the two previouslymentioned copending patent applications. In summary, our electrodeincludes a plurality of concentric tubes forming fluid inlet and uidoutlet passageways between tubes, and also forming a passageway forleads to the field coil located in the electrode face member which is inthe form of an annular cap. Our invention is characterized by animproved head structure facilitating the flow of the cooling fluid invarious paths and the passage of the various electrical leads, andincludes dual plug means for plugging up the central aperture at the topof the electrode and at the arcing end of the electrode. Our inventionhas improved heat shield means disposed on the outside of the outerannular tube for protecting this tube from the intense heat of radiationand convection from the arc and the melt, and limiting the amount ofheat removedfrom the furnace by the Water cooled surfaces of theelectrode. Our electrode is characterized by an improved detachable tipdescribed and claimed in the copending application of S. M. De Corso andCharles B. Wolf for Improved Electrode and Electrode Tip for UseTherein, tiled Mar. 17, 1965, Ser. No. 440,425 and assigned to theassignee of the instant invention.

We furthermore provide improved means including an aforementionedgravity maintained plug for enclosing the central aperture of theelectrode, both the plug means at the electrode face member, and theplug means at the head or top of the electrode, being removable bysliding out of the remote end of the electrod to permit materialintroduction and fuse material injection into the furnace through thecentral opening of the electrode.

Accordingly, a primary object of the invention is to provide a new andimproved non-consumable electrode.

A further object of the invention is to provide a new and improvednon-consumable electrode especially suitable for use in an electricfurnace.

Another object is to provide a new and improved nonconsumable electrodehaving passageway forming means for cooling uid and having improved heatshield means.

Another object is to provide a new and improved electrode of the typehaving a central aperture therethrough with improved means for closingthe aperture to prevent the escape of heat therethrough, the closuremeans being removable at will to permit material introduction throughthe central aperture.

Another object is to provide a new and improved electrode adapted tohave a `detachable electrode tip and arcing surface forming meanssecured thereto.

These and other objects will be more clearly apparent after a study ofthe accompanying drawings in connection with the accompanyingspecification.

In the drawings:

FIGS. lA and 1B together constitute a cross-sectional view through theelectrode according to the preferred embodiment thereof;

FIG. 2 is a plan view partially cut away of the electrode showing lluidconnections and electrical connections thereto; and

FIG. 3 is a fragmentary view of a modified heat shield arrangementaccording to a second embodiment of the invention.

Referring now to the drawings, in which like reference numerals are usedthroughout to designate like parts for a more detailed understanding ofthe invention, and in particular to FIG. lA thereof, there is shown abody 1 stem portion of the electrode generally designated 10, .nd havingfour concentric tubes or cylinders 11, 12, .3 and 14 as shown. Coolingfluid is seen to flow down passageway 16 between the tube 11 and tube12, these eing the two tubes of larger diameter, and uid flows |utthrough the passageway 17 between tubes 13 and 4, these latter two beingthe two tubes of smaller diam- `ter. It is preferred that the coolingfluid enter the elecrode through the passageway which is nearest to theube of larger diameter, that is, the outer of the concenric tubes. Wherethe arc 19, FIG. 1B, is produced and ustained by an alternating currentof power frequency, or example 60 cycles per sec., because of the skineffect he largest portion of the current is carried by the outer ube 11although all of the tubes are composed of equaly conductive material andall have equally good coniections with the head member 20 to which thecurrent Ource is connected as by means symbolized by lead 21. The largerportion of the alternating current for the arc lowing through tube 11tends to heat the tube 11 and also ends to heat up the next adjacentinner tube 12. For this eason, the relatively cold water or othercooling fluid hould preferably enter the electrode by the outerpasageway 16. This Water may have a temperature of 125 i. when it entersthe electrode, and may have the temerature raised to the order of 200 F.after it flows hrough the electrode face member or tip member adjalentthe arcing surface.

The aforementioned or upper head generally desiglated 20 includes a cap26 and an annular fluid input leader generally designated 23, The outertube 11 is een to have a plurality of bores 24 at spaced axial inervalsalong the length thereof near the upper portions, ows of the boresextending around the entire periphery f the tube, the bores 24communicating between pasageway 16 and the annular channel of theaforemenioned fluid header 23. As will be readily understood, a:onsiderable volume of water must be forced through the :lectrode tip ina short period of time in order to conluct away from the tip the greatheat fluxes generated Jy the intensely hot and high powered arc. Forexamlle, the arc may have a power of several megawatts, ind the currentinvolved may run as high as 80,00() arnaeres or more. Accordingly, watermay be supplied to he electrode at, for example, 500 pounds per squarench of pressure.

The upper end cap member 26 has an inner diameter uch that the innerannular edge 27 thereof snugly fits he outer surface of the upper end ofthe tube 14. rThe read 20 has a iiuid header channel 28 therein communi-:ating with a large bore or opening 29 through which luid leaves theelectrode. The plug 26 also has a portion i of somewhat enlarged innerdiameter to snugly lit he outside wall of the tube 13, surfaces 27 and30 being velded to tubes 14 and 13 respectively, as shown. The )lug 26also has cut away portions to form shoulders i1 and 32 for snuglyreceiving the ends of tubes 11 and i2 respectively, the tubes 11 and 12being welded to the :lug 26, as shown. The aforementioned headergeneraly designated 23 is annular in shape and is formed by a `leeveporton 34 snugly and securely mounted against a ihoulder formed by acut-away portion 35 in the outer zurface of plug 26 and is weldedtherein as shown, and he space between the sleeve 34 and the outersurface of he outer tube 11 is enclosed by an annular ring 37 weld- :dto both the tube 11 and the sleeve 34 by annular velds.

Fluid is brought to bore 42 in the header 23 through he pipe 41, therebeing a retaining member 43 having paced bores around the peripherythereof, two of these )eing shown at 44 and 45 for receiving bolts 46and 47 raving the threaded ends in threaded bores 48 and 49 'espectivelyin the plug or cap 26. Bore `42 passes through he cap and has mountedtherein one end of a filter 52.

It is seen in the aforementioned annular ring mem- 4 ber 37 there is athreaded bore S4 in which is normally disposed a plug 55, the plug beingremovable for cleaning purposes, etc.

The upper end 53 of the aforementioned filter is seen to terminatel in aring S6 which fits against a rather narrow annular shoulder S8 formed inthe aforementioned bore passageway 42, the filter 52 being retained inposition by the force of gravity thereon and the pressure of fluidentering through the pipe 41. Preferably the mesh of the lter 52 issufliciently small so that any foreign particle passing through the meshof the lter is small enough to pass through the cooling tubes orpassageways in the tip of the electrode as described in detail in theaforementioned copending patent application of Messrs. De Corso andWolf.

At another position on the plug or cap 26 and preferably diametricallyopposite to the coupling or retaining member 43, there is connectedanother pipe 61 with retaining member 62 secured to the plug 26 by volts63 and 64. Pipe 61 opens into aforementioned passage 29 and outletheader 28.

The central passageway 68 is normally closed at the upper or remote endthereof by a plug 69 having a bottom portion of reduced diameter forminga shoulder 70 which rests against the adjoining surfaces of the plug 26.Preferably, the plug 69 is composed of a heat resistant ceramic or otherrefractory material.

In the relatively wide annular passageway 18 formed between the tubes 12and 13, at a predetermined position therein, there are disposed theleads to an aforementioned field coil located in the tip for setting upa magnetic field adjacent the arcing surface of the electrode whichcauses the arc to move substantially continuously around the electrodetip. As explained more fully in the copending patent application ofMessrs. De Corso and Wolf, the field coil is wound of hollow copperconduit the turns of which are electrically insulated from each other,and a cooling uid ows through the conduit to conduct heat away from thecoil. One of the leads to the coil, shown in dashed line at 120 in FIG.1B, is provided by conduit 71, FIG. 1A, and the other lead to the coilis provided by conduit 72. Both of these leads are enclosed inelectrically insulating material as they pass up through the passageway18, the insulating sheath for conduit 72 being shown at 73, and it isseen that the upper end of the conduit 72 passes through a bushing 74composed of insulating material disposed in a bore 75 in the plug orclosure member 26.

Particular reference is made now to FIG. 3, a plan view of the upper endof the electrode. In FIG. 3, it is seen that the aforementioned pipes 61and 41 are bent near the cover member of the electrode to form elbows,and it is also seen that the aforementioned hollow conduits 71 and 72are bent in a manner to make a convenient connection to the electrode.Bushing 76 for lead 71 is also shown.

As will readily be understood by those skilled in the art, recallingthat the electrode of the invention is intended to be used in an arcfurnace, the electrode is subjected to very intense heat of radiation,and also very intense heat of convection of hot gases which may reachthousands of degrees in temperature. To this end, the outer tube 11 isenclosed in a ceramic heat shield formed of axially spaced sections, twoof the sections being shown at 481 and 82, FIG. 1A, each of the sectionsbeing formed in semicircular parts, the parts 81 and 81 being shown inFIG. 2, the section 81 being supported in position on the outer surfaceof the electrode by ring 83, FIG. 1A, welded to the surface of the tube.In FIG. 1B, the ceramic section parts 82 and 82' are seen to besupported by ring 84, and additional sections of the ceramic shield areshown at parts 86 and 86' supported by ring 87, and parts 88 and 88'supported by ring 89.

The aforementioned tube 1.2 is seen to have at the lower extremitythereof a portion of reduced outer diameter to form an annular space forreceiving the upper end of an annular ring supporting member 92 formingpart of a lower head which has a plurality of axially extending bores atspaced intervals around the entire perimeter thereof, two of theseaxially extending bores being shown at 93 and 94, fluid in the annularpassageway 16 passing through the multitude of bores 9'3 and 94 to` thefluid header 118 and thence through the lluid passageways 105 in theelectrode tip or electrode head generally designated 95. This ringsupport member 92 is shown in greater detail in the aforementionedcopending patent application of Messrs. De Corso and Wolf, Ser. No.440,425, lfiled Mar. 17, 1965, entitled Improved Electrode andiElectrodle Tip for Use Therein, now issued Parent No. 3,368,018. It maybe noted here that the ring support member `92 has an outwardlyextending flange portion 96, around the entire periphery of which thereare spaced bores for receiving bolts for retaining the tip 95 to theremainder of the electrode, two of these bolts being shown at 97 and 98.

It is seen that the lower end of the aforementioned tube 13 has at thelower extremity hereof a portion of increased inner diameter to form aspace for receiving the upper end of an additional annular supportingring member 101 forming a portion of the lower head having a pluralityof axial passageways 102 and 103 at spaced intervals around the entireperimeter thereof, passageways 102- and 103 communicating with anannular water header 104 in the tip generally designated 95, the waterheader 1014- communicating with the fluid passageways 105. Ring supportmember 101 is shown in greater detail in the aforementioned copendingvpatent application of Messrs. De Corso and Wolf, as are additionaldetails of the water headers 104 and 118, and the passageways 105 in theelectrode tip generally designated 9S. It is noted, however, that thering support member 101 has an inwardly extending annular flange portion107 having axially extending bores therethrough at spaced intervalsaround the entire flange for receiving additional bolts for retainingthe tip 95 to the rest of the electrode structure, two of the boltsbeing shown at 111 and 112. Portions 92 and 101 of the lower head aresecured rigidly in place with respect to each other as shown.

Disposed in the aforementioned central opening 68 is a plug 114preferably composed of ceramic or other very refractory material, theannular edge 115 of the ceramic plug resting against the aforementionedflange 107 and being retained in place by the force of gravity thereon.

The electrode tip is described and claimed in the aforementionedcopending patent application as being composed of a highly heatconductive and electrical conductive material such as copper, having aplurality of generally U-shaped passageways around the entire annulararcing surface, water entering the passageways by the header 118 andleaving by the aforementioned header 104.' The iield coil is shown at`120.

Particular reference is made now to FIG. 3, which shows a ceramic heatshield according to a second embodiment of the invention. In theembodiment of FIG. 3, the outer tube 11 has a plurality of Studs 128extending from the surface thereof, and the ceramic coating is appliedto the tube, the ceramic coating being shown at 131 and held in place byclinging to the aforementioned studs.

The structure may be strengthened by providing ribs or struts, not shownfor convenience of illustration, connecting adjoining tubes of the groupof tubes 11, 12, 13 and 14. Furthermore, a honeycomb structure for pairsof `tubes may be employed if desired. Additional ease of constructionand strength can be obtained by the use of extruded tubes, if desired ofaluminum, at 11, 12, 13 and 14.

As aforementioned, the inside of tube 14 is a central aperture orpassageway 68 which provides a corridor for introducing material intothe furnace, including fuse material. lf desired, means may be attachedto the plug 114 for removing the plug by way of the upper end of thepassageway 68 without necessitating removal of the electrode from thefurnace.

The inside aluminum tube structure can ilex relative to the outsideproviding for a good mating to eccentricities.

The tubes may be coated to increase their electrical conductivity ifdesired.

The construction of the electrode permits the use of high pressure wateror other cooling fluid, increasing the rate of Lflow and increasing theheat ilux which may be removed by the water. Furthermore, the apparatusis admirably suited for high fluid velocity. This provides maximumcooling capability, and the pressure drop in the cooling fluid may befrom, for example, 500 p.s.i. in cylindrical inlet passageway 16 to, forexample, 100 p.s.i. in the outlet passageway 17.

If desired, tubes 13 and 14 may be welded or [outerwise] otherwisesecured together and made removable as a unitfrorn the other tubes, asuitable head corresponding to head 20 being provided.

Whereas we have shown and described our invention with respect to someembodiments thereof which give satisfactory results, it should beunderstood that changes may be made and equivalents substituted withoutdeparting from the spirit and scope of the invention.

We claim as our invention:

1. In an electrode for use in an arc furnace, in combination, an annularelectrode tip composed of non-magnetic material having good electricaland thermal conductivity and providing an arcing surface, the electrodetip having a plurality of generally U-shaped passageways therein for theflow of a cooling fluid near the arcing surface, an electrode bodyportion comprising a plurality of concentric tubes and having the tipmounted at one end thereof, at least one of the tubes being composed ofelectrically conductive material for bringing electrical current toproduce and sustain an arc from the tip, the tubes being of graduateddiameters and spaced from each other to form a plurality of cylindricalpassageways therebetween, one cylindrical passageway between the outertube and the next adjacent tube bringing a cooling iluid to theelectrode tip, another cylindrical passageway conducting fluid from theelectrode tip, a magnetic eld producing coil disposed in the electrodetip, means passing through the electrode body portion for bringing anenergizing `potential to the magnetic field producing coil, inlet fluidheader means and outlet fluid header means disposed at the other end ofthe electrode body portion, the inlet fluid header means including meansforming an annular chamber encircling the outer tube at said other endof the electrode body portion, said outer tube having a plurality ofaxially spaced and circumferentially spaced bores therethrough aroundthe entire tube adjacent the inlet fluid header means forming fluidpassageways between the annular chamber and said one cylindricalpassageway, the inlet and outlet fluid header means being adapted tohave fluid conduit means connected thereto, and heat shield meansdisposed around the outside of the tube of largest diameter forprotecting said last-named tube from heat of convection and radiationfrom the arc and for limiting the amount of heat removed from thefurnace by the fluid cooled surfaces of the electrode.

2. An electrode according to claim 1 additionally characterized in thatthe tube of smallest diameter forms a central opening extendingsubstantially the entire length of the electrode body portion, thecentral opening of the annular tip having a diameter substantially equalto that of the tube of smallest diameter whereby a corridor is formedfor feeding material into the furnace through the electrode, andincluding in addition removable means for plugging up the corridor ofthe electrode at the annular tip end of the electrode, and otherremovable means for plugging up the corridor of the electrode at theother end of the electrode.

3. Electrode apparatus comprising, in combination, an electrode bodyportion including a plurality of concentric ubes of lgraduateddiameters, the tubes being spaced from :ach other to form a plurality ofcylindrical passageways herebetween, a generally annular cup membermounted it one end of the body portion composed of a highly heat:onductive material and having an inner cylindrical wall iortion, anouter cylindrical wall portion, and a bottom vall portion forming anarcing surface, a plurality of gen- :rally U-shaped tubes disposedwithin the annular cup nember extending axially along both cylindricalwall porions and across the bottom wall portion of the annular :upmember, the U-shaped tubes being disposed at spaced ntervals around theentire periphery of the annular cup nember, a field coil disposed in theannular cup member yor setting up a magnetic field adiacent the arcingsurace of the annular cup member to substantially coninuously move thearc in an annular path around the aniular cup member, one of saidcylindrical passageways :onducting fluid to the plurality of generallyU-shaped ubes in the annular cup member, another of said cylinlricalpassageways conducting fluid from the plurality of generally U-shapedtubes in the annular cup member, an idditional cylindrical passagewaycontaining lead means for the eld coil, fiuid inlet header and fluidoutlet header neans at the other end of the electrode body portions, hefluid inlet header means including means forming an innular chamberencircling the outer tube of said plurality if concentric tubes andhaving a plurality of axially spaced 1nd circumferentially spaced boresforming iiuid passagevays between the annular chamber and said onecylinlrical passageway, means at the annular cup member for :losing thetube of smallest diameter, and means for closng the tube of smallestdiameter at the other end of the :lectrode body portion.

4. Electrode apparatus according to claim 3 including n addition heatshield means composed of refractory maerial substantially enclosing theouter of said plurality )f concentric tubes along the entire lengththereof, the ieat shield means including axially spaced sections each:upported by an annular ring secured to the outer of the :oncentrictubes, each section including two semi-cylinlrical portions.

S. A non-consumable are electrode comprising, in comination, electrodeface means composed of nonmagletic, conductive material and providing anarcing surtace, magnetic field producing means disposed near the trcingsurface of the electrode face means, the electrode :'ace means beingannular in shape and having a plurality )f generally U-shapedpassageways therein, the U-shaped :assageways being at spaced intervalsaround the periph- :ry of the electrode face means and providing meansfor he ow of a cooling fluid near the arcing surface, a ubular structurecomposed at least partially of conducive material supporting themagnetic field p-roducing neans and the electrode face means and makingelectrical :onnection with the electrode face means, the tubularytructure including means providing a plurality of passagevays includingat least one annular passageway for the low of a cooling fluid to thepassageways in the electrode ace means and at least another annularpassageway for :onducting fluid from the passageways in the electrode'ace means, the conductive portion of the tubular strucure being adaptedto have a source of electrical potential :onnected thereto for producingan arc from the arcing `ur'face of the electrode face means, themagnetic field :ausing the arc to move substantially continuously overzaid arcing surface, and thermally" insulating means disiosed around theoutside of at least a portion of the ubular structure adjacent theelectrode face means, the hermally insulating means including axiallyspaced secions of refractory material, each axially spaced sectionncludng two semi-cylindrical portions.

6. A non-consumable arc electrode according to claim 5 including inaddition, water header means disposed at he end of the electrode awayfrom the electrode face neans, the water header means including meansforming an annular chamber encircling the tubular structure andcommunicating with said one annular passageway.

7. A non-consumable electrode according to claim 5 in which theelectrode is additionally characterized as having a large centralpassageway therethrough and as having means at the electrode face meansforming a first annular shoulder and means at the other end of theelectrode forming a second annular shoulder, and including in additionremovable plug means composed of refractory material closing the centralaperture at the end of the electrode adjacent the electrode face meansand normally supported by said first annular shoulder, and otherremovable plug means composed of refractory material closing the centralaperture at the other end of the electrode and normally supported bysaid second annular shoulder.

8. A non-consumable arc electrode comprising, in combination, a tubularstructure including a first sleeve and forming a first passageway, asecond sleeve disposed around the first sleeve coaxially therewith, atleast one of the rst and second sleeves being composed of conductivematerial, the second sleeve being of greater diameter and forming anadditional passageway between the second sleeve and the first sleeve,electrode head means at one end of the tubular structure including fluidinlet means and fluid outlet means communicating selectively with thefirst passageway and the additional passageway between the first sleeveand the second sleeve, the fluid inlet means including header means inthe shape of an annular chamber encircling the tubular structure, filtermeans in the header means, fluid cooled annular electrode face meansmounted at the other end of the tubular structure and providing anarcing surface, the fluid cooled annular electrode face means includingan annular tip having a plurality of generally U-shaped passagewaystherein near the arcing surface, the U-shaped passageways of the annularelectrode face means being Operably connected to the fiuid inlet meansand fluid outlet means by way of the rst passageway and the additionalpassageway, a field coil supported by the tubular structure near thearcing surface of the electrode face means, means including the sleeveof conductive material forming an electrical circuit between theelectrode face means and the electrode head means, and means connectedto the field coil for energizing the coil to set up a magnetic field atthe arcing surface of the electrode face means.

9. A non-consumable arc electrode comprising, in combination, a tubularstructure including fluid inlet and fluid outlet means, sleeve meansforming a fluid inlet passageway extending axially of the tubularstructure and other coaxially disposed sleeve means forming a fluidoutlet passageway, an annular electrode face member composed ofconductive, non-magnetic material, the electrode face member includingan annular tip, the annular tip having a plurality of generally U-shapedpassageways therein, each of the U-shaped passageways passing near thearcing surface of the annular tip, the U-shaped passageways beingdisposed at closely spaced intervals around the entire periphery of thetip, cylindrical fluid channeling means extending bet-Ween one of saidfluid passageways and the corresponding ends of all of the plurality ofU-shaped passageways, other cylindrical fluid channeling means extendingbetween the other of the fluid passageways and the other ends of all ofthe U-shaped passageways, coil means disposed within the annular tip,lead means for bringing an electrical current to the coil means to setup a magnetic field at the arcing surface of the electrode tip, meansfor applying an electrical potential to the electrode tip to form an arctherefrom, the magnetic field causing the arc from the electrode tip tomove substantially continuously in a substantially circular path aboutthe annular arcing surface of the electrode tip, said circular pathcutting across substantially all of the U- shaped passageways, and heatshield means composed of highly heat resistive material disposed aroundthe outside of at least a portion of the tubular structure adjacent theelectrode face member, the heat shield means including axially spacedsections each supported by an annular ring secured to the tubularstructure, each section including two semi-cylindrical portions.

10. A non-consumable arc electrode for use in an electric furnacecomprising, in combination, annular electrode face means composed ofnon-magnetic, conductive material providing an arcing surface, magneticfield producing means disposed in the electrode face means, theelectrode face means having a plurality of generally U-shapedpassageways therein, cach of the U-shaped passageways passing near thearcing surface, the U-shaped passageways being at closely spacedintervals around the entire periphery of the annular electrode facemeans, a tubular structure composed at least partially of conductivematerial supporting the magnetic field producing means and the electrodeface means and making electrical connection with the electrode facemeans, and heat shield means external to at least a portion of thetubular structure, the heat shield means including a plurality ofaxially spaced sections each supported by and attached to a plurality ofstuds extending from the outer surface of the tubular structure, thetubular structure having a large central aperture and including meansproviding concentric passageways for the flow of a cooling fluid to thepassageways in the electrode face means and conducting fluid from thepassageways in the electrode face means, the conductive portion of thetubular structure being adapted to have a source of electrical potentialconnected thereto for producing an arc from the arcing surface of theelectrode face means, the magnetic field causing the arc to movesubstantially continuously over said arcing surface.

11. An electrode according to claim including in addition removable plugmeans composed of a highly heat resistant material mounted in theannular electrode face means and reducing the amount of heat whichreaches the interior of the tubular structure from the furnace, andother removable plug means composed of a highly heat resistant materialmounted in the central aperture at the other end of the electrode, theremovable plug means and other removable plug means being removed topermit the vintroduction of material into the furnace through thecentral aperture of the electrode and being thereafter replaced.

12. In a non-consumable electrode, in combination, inner and outerconcentric means forming first and second channels respectively for theflow of cooling fluid and providing a central aperture extending axiallythrough the electrode, first annular fluid channeling and supportingmeans secured at one end thereof, second annular fluid channeling andsupporting means secured at said last-named end thereof, annularelectrode face means mounted on the first and second fluid channelingand supporting means, the annular electrode 'face means including anannular tip forming an arching surface, said annular tip having aplurality of generally U-shaped passageways therein, each of saidpassageways passing near the arcing surface of the tip, said passagewaysbeing located at closely spaced intervals around the entire periphery ofthe tip and providing for the flow of a cooling fluid near the archingsurface, magnetic eld producing means disposed Within the electrode facemeans and having lead means for bringing an energizing potentialthereto, and first and second plug 4members composed of a highly heatresistive material disposed in the central aperture of the electrode atboth ends thereof and-closing the central aperture against the passageof heat flux therethrough.

13. An electrode according to claim 12 including in addition fluid inletheader means and fluid outlet header means disposed at the end of theelectrode away from the annular electrode face means, the fluid inletheader means including means forming an annular chamber lencircling theouter concentric means and having a plurality of axially spaced andcircumferentially spaced bores cornmunicating with the second channelformed by the outer concentric means.

14. In a non-consumable electrode, in combination, an annular electrodeface member adapted to be fluid cooled, the electrode face memberincluding an annular tip having a plurality of generally U-shapedpassageways therein, each of the U-shaped passageways passing near thearcing surface of the annular electrode face mem-ber, a field coildisposed within the tip, means including cylindrical fluid channelingmeans for bringing a cooling fluid to the electrode face member, meansincluding other cylindrical fluid channeling means for conducting fluidfrom the electrode face member, fluid inlet header means and fluidoutlet header means communicating with the fluid channeling means and`the other fluid channeling means respectively, the fluid inlet headermeans including means forming an annular chamber encircling theelectrode and having a plurality of fluid passageways for conductingfluid therefrom, fluid filter means in the annular chamber, and plugmeans including at least one removable plug composed of a highly heatresistant material mounted in the central aperture of the electrode andpreventing the passage of heat flux therethrough.

15. An electrode comprising, in combination, a tip composed ofnon-magnetic, highly heat conductive material, the tip lbeing generallyin the shape of an annular cup forming an arcing surface, the electrodetip lhaving a plurality of spaced generally U-shaped passagewaysextending around the entire periphery of the cup, the electrode tiphaving a field coil disposed therein for setting up a magnetic field atthe arching surface of the tip, an electrode Ibody portion supportingthe tip at one end of the body portion, the electrode body portionincluding a plurality of concentric tubes of graduated diameters, atleast one of said tubes being composed of electrically conductivematerial, and fluid inlet means and fluid outlet means at the other endof the electrode body portion, the spaces between the concentric tubesconducting fluid from the fluid inlet means to the electrode tip andconducting iluid from the electrode tip to the fluid outlet means, thefluid inlet means including means forming an annular chamber encirclingthe electrode body portion and having a plurality of axially spaced landcircumferentially spaced fluid passageways in the inner wall thereof.

16. An electrode according to claim 15 including in addition tworemovable plug means for closing the ends of the electrode, each of theplug means being composed of refractory material.

17. An electrode for electric are furnaces comprising an upper head, alower head of conductive material, a conductive metal structureconnecting said heads, an electrode head carried by said lower head, anda ceramic covering enclosing said metallic structure.

.78. In an electrode as claimed in claim 17, said metallic structureincluding conducting means for a cooling medium.

I9. In an electrode as claimed in claim 17, said upper and lower headsbeing hollow and said metallic structure comprising tubes connectingsaid upper and lower heads.

20. In an electrode as claimed in claimt 17, said upper head, metallicstructure and ceramic covering having a central longitudinal holetherein.

21. In an electrode as claimed in claim 20, said electrode head having ahole therein communicating with said longitudinal hole.

22. An electrode for electric arc furnaces comprising an upper head, tworadially spaced annular ring supporting members composed of conductivematerial near the lower end of the electrode, a conductive metalstructure connecting the upper head and the two radially spaced annularring supporting members, an electrode tip carried by said two radiallyspaced annular ring supporting members, and a ceramic covering enclosingsaid metallic structure.

23. In an electrode as claimed in claim 22, said metallic rtructureincluding conducting means for a cooling nedium.

24. In an electrode as claimed in claim 22, said upper read being hollowand said two radially spaced annular ing supporting members each havinga plurality of axially fxtending passageways therethrough at spacedintervals tround the entire periphery thereof, and said metallic:tructure comprising tubes connecting said upper head and 'aid tworadially spaced annular ring supporting members.

25. In an electrode as claimed in claim 22, said upper lead, metallicstructure and ceramic covering having a rentra] longitudinal holetherein.

26. In an. electrode as claimed in claim 25, said elecrode tip having ahole therein communicating with said ongitudinal hole.

27. An electrode comprising a body or stem portion It least partiallycomposed of conductive material, an electrode head composed ofconductive material carried 1y the stem portion at the lower endthereof, and' heat hield means external to the stem portion, the stemportion ind electrode head having mutually communicating ixiallyextending passageways therethrough whereby an zxial opening extends fromthe top of the steam portion he length of the electrode.

28. An electrode according to claim 27 wherein the ftem portion includesfluid channeling means for conlucting a cooling fluid from the upper endthereoyL toward he electrode head, the fluid channeling means alsoconlucting fluid after it has performed its cooling function oward theupper end of the stem portion.

29. An electrode according to claim 27 in which said stem portionincludes a plurality of concentrically mounted tubes radially spacedfrom each other.

30. An electrode comprising a body or stem portion, an electrode headcarried by the stem portion at the lower end thereof and heat shieldmeans external to the stem portion, the stern portion including fluidchanneling means for conducting a cooling fluid from the upper endthereof toward the electrode head, the fluid channeling means alsoconducting fluid after it has performed its cooling function toward theupper end of the stem portion, the stern portion ana' electrode headhaving mutually communicating axial passageways therethrough whereby anaxial passageway extends from the top of the stem portion' the length ofthe electrode.

References Cited The following references, cited by the Examiner, are ofrecord in the patented le of this patent or the original patent.

UNITED STATES PATENTS 2,093,821 9/1937 Southgate Z39-288.5 2,472,8516/1949 Landis S15-347 3,130,292 4/1964 Gage et al. 219-75 3,307,0112/1967 Baird 219-*74 BERNARD A. GILHEANY, Primary Examiner R. N. ENVALL,JR., Assistant Examiner

